Mode changeover mechanism for tape recorders

ABSTRACT

A mode changeover mechanism for tape recorders is provided in which any solenoid is not used, and in which a capstan gear is rotated and a gear arm is turned by a motor rotatable in opposite directions to selectively rotate a supply or take-up reel, and the engagement of the capstan gear with an assist gear having a toothless segment is controlled by the turning of the gear arm to vary the position of a head plate by eccentric and changeover cams formed on the assist gear, thereby changing the operation modes of a tape recorder.

FIELD OF THE INVENTION

The present invention relates to a mode changeover mechanism for taperecorders used for telephone message recorders, etc.

BACKGROUND OF THE INVENTION

Heretofore, tape recorders used for telephone message recorders havebeen designed such that the "record/playback", "rewind", "fast forward"and "stop" modes are remote-controllable. In order to make such remotecontrol feasible, it has been proposed to (1) directly operate thechangeover levers for the individual modes by a solenoid, (2) engage anassist cam gear with a gear rotated by a main motor by a solenoid,thereby operating a head plate with an assist gear, and so on.

However, problems with the use of such a solenoid as mentioned aboveare:

(1) the power to be consumed is so increased that a power source sectionis increased in size, resulting in increased costs,

(2) the volume and weight of a mechanical section are increased, and

(3) some limitation is imposed upon the position of the mechanicalsection to be used by reason that since there is a variation in thesuction force depending upon whether the plunger is moved vertically orhorizontally, it is desired for a wall type of telephone messagerecorder that the plunger be located horizontally.

SUMMARY OF THE INVENTION

In consideration of the foregoing problems, an object of the presentinvention is to provide a mode changeover mechanism for tape recorders,in which a sliding forward movement of a head plate and a change of"playback" and "fast forward" positions are achievable with eccentricand changeover cams of an assist gear without recourse to any solenoid,which makes contribution to current and space savings and reductions incost, and which can be used in any free position.

According to the present invention, the above object is achieved by theprovision of a mode changeover mechanism for tape recorders comprisingin combination:

a motor rotatable in opposite directions,

a capstan gear rotatable in unison with a capstan shaft by said motor,

a gear arm provided such that it is rotatable in the direction ofrotation of said capstan shaft,

two gears rotatably supported on said gear arm such that they are alwaysin mesh with said capstan shaft to selectively drive a supply reel or atake-up reel,

an assist gear having a toothless segment and whose engagement with saidcapstan gear is controlled by the turning of said gear arm,

an eccentric cam and a changeover cam formed on said assist gear, and

means for controlling the position of a head plate to slide forth saidhead plate by said eccentric cam and change said head plate to a"playback" or "fast forward" position.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willnow be apparent from a reading of the following detailed descriptionwith reference to the accompanying drawings, which are given for thepurpose of illustration in which:

FIG. 1 is a plan view showing part of the mode changeover mechanism fortape recorders according to the present invention, as viewed through abase plate in the "record/playback" mode,

FIG. 2 is a plan view of that mode changeover mechanism,

FIG. 3 is a perspective view of a biasing mechanism in which a spring ismounted to slide a head plate back and forth,

FIG. 4 is a plan view of part of the mode changeover mechanism for taperecorders in the "stop" and "rewinding" modes,

FIG. 5 is an enlarged plan view of a gear arm and an assist gear shownin FIG. 1,

FIG. 6 is a plan view of part of the mode changeover mechanism for taperecorders, as viewed through a base plate in the "stop" and "rewind"modes,

FIG. 7 is an enlarged view of a gear arm and an assist gear shown inFIG. 6, and

FIG. 8 is a plan view of the mode changeover mechanism for taperecorders, as viewed through a base plate in the "fast forward" mode.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1 and 2 which are plan views of one embodiment ofthe mode changeover mechanism for a tape recorder in the"record/playback" mode, the tape recorder typically includes a baseplate 1 formed of a resin and a head plate 2 placed thereon. A pin shaft10 fixed to an assist arm 3 is rotated by an eccentric cam 4a of anassist gear 4 to move the head plate 2 back and forth, and a pinchroller 12 rotatably supported on the head plate 2 engages a capstanshaft 13 by a pin 11.

Referring to FIG. 2, since a protrusion 2a is pushed the head plate 2 isdesigned to return to a "stop" position, as shown in FIG. 3, by a spring14 held by a spring supporter 1a and a spring retainer 1b.

As illustrated in FIGS. 1 and 2, the assist arm 3 is rotatably supportedon the base plate 1 by a screw shaft 15, and is biased in thecounterclockwise direction by a spring 16 provided between its one end3a and the head plate 2. In the "stop" mode shown in FIG. 4, the assistarm 3 abuts on its one side 3b against a bend 2b. The pin shaft 10 fixedto the assist arm 3 extends through a through-hole (not shown) in thebase plate 1 and a through-hole 2c in the head plate 2 to a positionwhere it faces and can abut against the eccentric cam 4a or a changeovercam 4b of the assist gear 4.

The base plate 1 is fixedly provided with reel shafts 17 and 18 in anupward manner, which receive rotatably therethrough a tape take-up reelholder 19 and a tape feed reel holder 20. The tape take-up and supplyreel holders 19 and 20 are respectively provided with a take-up reelgear 21 and supply reel gear 22 through the respective associatedfriction mechanisms, so that any rotational force more than the presettorque is not transmitted thereto. Rotatably supported on the base plate1 is a fly-wheel 23 having the capstan shaft 13 as an integral piece, asillustrated in FIG. 1, said capstan shaft 13 extending upwardly throughthe head plate 2. The fly-wheel 23 is rotatably driven by a motor 25rotatably in opposite directions through a belt 24 provided along and ina peripheral groove.

The capstan shaft 13 is fixed with a capstan gear 26 and provided with agear arm 5 rotatable in the rotational direction thereof through afriction mechanism. As illustrated in FIGS. 1 and 5, on both sides ofthe gear arm 5 there are gears 27 and 28 in constant mesh with thecapstan gear 26, which are rotatably supported on shafts 29 and 30. Onecombination of gear 27 with shaft 29 is provided with a frictionmechanism for applying thereto a load suitable to rotate the gear arm 5per se by the rotation of the capstan gear 26. On one side within aregion in which the gear arm 5 turns, the base plate 1 is provided witha toothed projection 1c to be in mesh with the gear 27. On both sides ofthe gear arm 5, there are provided bent pieces 5a and 5a which areinserted into window openings (not shown) in the base plate 1 to limitthe range of rotation thereof. Additionally, a protrusion 5b is providedon one side of the center of the gear arm 5.

The base plate 1 is fixedly provided with a downward shaft 31 forrotatably supporting the assist gear 4, which is located in a positionwhere it can mesh with the capstan gear 26.

The assist gear 4 is provided on its outer periphery with toothlesssegments 4c and 4d, which are in turn provided with triggeringengagement means 4e and 4f, defined by pins, to be pushed with theprotrusion 5b of the gear arm 5.

The head plate 2 is provided thereon with a recording/reproducing head32 and an erasing head 33.

Referring to the operation of the mode changeover mechanism of the taperecorder, when the motor 25 is driven in a direction shown by an arrow Pto rotate the fly-wheel 23 in the clockwise direction for changing the"stop" mode shown in FIGS. 4 to 7 to the "record/playback" mode shown inFIGS. 1, 2 and 5, the gear arm 5 is integrally turned in the clockwisedirection so that the gear 27 in constant mesh with the capstan gear 26meshes with the take-up reel gear 21, since a load is applied to betweenthe gear arm 5 and the capstan gear 26 through the friction mechanismprovided for the combination of gear 27 with shaft 29.

In the "stop" mode, one toothless segment 4d of the assist gear 4 isthen located in a position opposite to the capstan gear 26, asillustrated in FIGS. 6 and 7. During the turning of the gear arm 5,however, the triggering engagement pin 4f is pushed by the protrusion 5bto cause the assist gear 4 to rotate in the counterclockwise direction.This in turn permits the assist gear 4 to mesh with the capstan gear 26,which then makes a half turn.

As a counterclokwise force of rotation is applied to the eccentric cam4a through such a half turn, the pin shaft 10 is moved along an innercam surface 4g of the eccentric cam 4 toward its center to turn theassist arm 4. The spring 16 permits the assist arm 3 to be abuttedagainst the bend 2b by the movement of the pin shaft 10, so that whenthe pin shaft 10 is moved forth with a force smaller than that of thespring 16, the head plate 2 is slid forth integrally therewith. If thehead plate 2 is further moved forth until the pinch roller 12 contactsthe capstan shaft 13 with a tape located therebetween, as illustrated inFIG. 2, then the sliding movement of the head plate 2 is stopped so thatthe "record/playback" mode is ready to operate. However, the assist gear4 continues to rotate further to turn only the assist arm 3 around thescrew shaft 15, so that its one side 3b is spaced from the bend 2b andthe pin shaft 10 passes through the innermost portion of the eccentriccam 4. Thereafter, upon the other toothless segment 4c of the assistgear 4 reaching the position of the capstan gear 26, the capstan gear 26disengages the assist gear 4, the rotation of the assist gear 4 isstopped.

After the pin shaft 10 has passed through the innermost portion of theeccentric cam 4a, it is locked by the spring 16 in a V-shaped notch inthe changeover cam 4b. Since the one side 3b of the assist arm 3 islocated in a position where it comes in no contact with said bend 2b,however, the pinch roller 12 is pushed against the capstan shaft 13 bythe spring 16, while the tape is fed from within a tape cassette towardthe tape take-up reel holder 19 at a constant speed. The protrusion 5bof the gear arm 5 is located on the left side of the triggeringengagement means 4e.

For a conversion to the "fast forward" mode, the motor 25 is slightlyrotated in a direction shown by an arrow R in the "record/playback"mode. This then causes the gear arm 5 to be turned, while the triggeringengagement means 4e is pushed by the protrusion 5b of FIG. 5, so thatthe assist gear 4 is slightly rotated by such triggering means in theclockwise direction. This rotation in turn causes the pin shaft 10 todisengage the changeover cam 4b and take the position of FIG. 8, so thatthe head plate 2 is restored to the "stop" position.

When the motor 25 is then again rotated in the direction shown by thearrow P, the "fast forward" mode of FIG. 8 is achieved. Such motorcontrol is performed by an electronic circuit. With the gear arm 5turned in the clockwise direction, the tape is fed from within the tapecassette toward the tape take-up reel holder 19, since the gear 28meshes with the take-up reel gear 21, as is the case with the"record/playback" mode.

At this time, the tape is wound up at a high speed, since the head plate2 takes the same position as the "stop" position. It is here understoodthat higher revolutions per minute of the motor 25 will result in higherspeed-winding of the tape.

When the "record/playback" /"fast forward" mode is converted to the"stop" mode, the motor 25 is rotated in the direction shown by the arrowR in the "record/ playback" mode of FIG. 5 and the "fast forward" modeof FIG. 8. During the turning of the gear arm 5, the triggeringengagement means 4a is pushed by the protrusion 5b, whereby the assistgear 4 is rotated in the clockwise direction. This rotation then causesthe assist gear 4 to mesh with the capstan gear 26 for rotation. Thisrotation in turn causes the pin shaft 10 to be moved along an outer camsurface 4h of the eccentric cam 4a. The outer cam surface 4h serves topush down the pin shaft 10 below the "stop" position. Thereafter, thepin shaft 10 is restored by the spring 16 to the "stop" position at thefinal end of the outer cam surface 4h, and the capstan gear 26disengages the assist gear 4 in a position where the toothless segment4c of the assist gear 4 is opposite to the capstan gear 26, so that themotor 25 stops into the "stop" mode of FIG. 6.

For a conversion to the "rewind" mode, the motor 25 is rotated in thecounterclockwise direction shown by the arrow R in the "stop" mode ofFIG. 6.

A conversion from the "rewind" mode to the "stop" mode may be achievedby stopping only the rotation of the motor 25.

With the mode changeover mechanism for tape recorders, as constructedabove, it is possible to decrease the power to be consumed and, hence,reduce the size and weight of the power source section, thus resultingin decreases in cost, since, without recourse to any solenoid, the headplate 1 is moved back and forth by the triggering means for pushing thetriggering engagements 4e and 4f of the assist gear 4 with theprotrusion 5b of the gear arm 5, thereby controlling the engagement ordisengagement of the pinch roller 12 with or from the capstan shaft 13.Furthermore, since the conversion of operational modes takes onlydepending upon the direction of rotation of the motor 25, such avariation as occurs with the use of a solenoid is unlikely to be inducedin the suction characteristics depending upon the position of themechanical section to be mounted in place. Thus, design can be made witha high degree of freedom. Noises generated from the mechanical sectioncan also be reduced due to no use of any solenoid.

Moreover, the changeover operation can take place so rapidly that thelength of waiting time can be reduced, since the "playback" and "fastforward" positions can be changed in the position where the changeovercam 4b is engaged with and locked by the pin shaft 10 and the rewindingof the tape can be merely achieved by the rotation of the motor 25.

When incorporated into a telephone message recorder, the operation ofthe above mode changeover mechanism for tape recorders involves arepetition of calling-up→announcing by a voice synthesizing IC, etc.→recording of message by the actuation of motor→calling-off→stopping ofmotor followed by waiting.

The operation for the reproduction of message involves a repetition ofreleasing→rewinding of tape by the actuation of motor→initiation of tapesupplying reproducing of message by the rotation of motor→completion ofplayback→rewinding of tape by the rotation of motor→stopping of motorfollowed by waiting.

As many modifications may be made to the embodiments of the invention,it is intended that all arrangements contained herein be interpreted asillustrative of the invention and not in a limiting sense.

What is claimed is:
 1. A mode changeover mechanism for tape recorderscomprising in combination:a motor rotatable in opposite directions, acapstan gear rotatable in unison with a capstan shaft by said motor, agear arm provided such that it is rotatable in the direction of rotationof said capstan shaft, two gears rotatably supported on said gear armsuch that they are always in mesh with said capstan shaft to selectivelydrive a supply reel or a take-up reel, an assist gear having a toothlesssegment and whose engagement with said capstan gear is controlled by theturning of said gear arm, an eccentric cam and a changeover cam formedon said assist gear, and means for controlling the position of a headplate to slide forth said head plate by said eccentric cam and changesaid head plate to the "playback" or "fast forward" position.
 2. Amechanism as claimed in claim 1 wherein said controlling means includesa turnably provided assist arm and a pin shaft provided on said assistarm, said pin shaft being engageable with said eccentric cam orchangeover cam to control the position of said head plate.